1. Technical Field
The technical field generally relates to a printing apparatus, and more particularly, to a three-dimensional printing apparatus (3-D printing apparatus).
2. Description of Related Art
Along with the progress of computer-aided manufacturing (CAM), the manufacturing industry has developed a brand-new printing technique, the 3-D printing technique, which is able to quickly make an initial design idea into a fabricated object. In fact, the 3-D printing technique is a collective term of a series of rapid prototyping techniques (RP techniques) based on a lamination fabrication, where the cross-sectional layers with different shapes of a work piece are produced by an RP machine through scanning with the X-Y plane in association with stepped displacements in a layer thickness by a layer thickness so as to finally form a 3-D object. The 3-D printing technique has no limitation of geometric shape. The more complicate a part is, the more excellent the RP technique performs. In addition, the RP technique can largely save labor and process time so that it can truly make a digital 3-D model information designed by a 3-D computer-aided design (CAD) software in present under a shortest time requirement, wherein, the digital 3-D model, not only, can be touched, but also its geometric curves can be felt, even the user can trial the assembling performance of a part and conduct the possible function test.
Currently, many methods of forming a plurality of thin cross-sectional layers. For example, a printing head can move in X-Y coordinates on a base according to the X-Y-Z coordinate values established by the design data of a 3-D model, and meanwhile, a modeling material is sprayed out to produce layers with correct cross-sectional shapes. Then, the deposited material gets naturally hardened or cured by using, for example, a strong light source so as to form the required cross-sectional layers, followed by curing layer by layer to form a 3-D object. The forming approach is different depending on the material property. For example, for a fusing/softening plastic material to serve as the “ink” of the 3-D printing, the RP technique can adopt, for example, the selective laser sintering (SLS) and the fused deposition modeling (FDM).
Since the aforementioned spraying printing head is mostly composed of a gear set, tubes and a nozzle, so that the fused or softened modeling material easily remains at the gapped places. Once the modeling material is cured, the residual modeling material will be choked therein to affect the subsequent normal operation of the parts.